The NET Bible has this to say on Jer. 5:8 which says: "They were like well-fed stallions wild with desire, each lusting for his neighbor's wife." (New Simplified Bible)
NET Bible: "The meanings of these two adjectives are uncertain. The translation of the first adjective is based on assuming that the word is a defectively written participle related to the noun “testicle” (a Hiphil participle ??????????? [ma’ashikhim] from a verb related to ??????? [’eshekh, “testicle”]; cf. Lev 21:20 ) and hence “having testicles” (cf. HALOT 1379 s.v. ??????) instead of the Masoretic form ?????????? (mashkim) from a root ?????? (shakhah), which is otherwise unattested in either verbal or nominal forms. The second adjective is best derived from a verb root meaning “to feed” (a Hophal participle ????????? [muzanim, the Kethib] from a root ???? [zun; cf. BDB 266 s.v. ????] for which there is the cognate noun ?????? [mazon; cf. 2 Chr 11:23 ]). This is more likely than the derivation from a root ????? ([yazan]reading ??????????? [mÿyuzzanim], a Pual participle with the Qere) which is otherwise unattested in verbal or nominal forms and whose meaning is dependent only on a supposed Arabic cognate (cf. HALOT 387 s.v. ?????)."